GENEVA (Reuters) - Mutilated bodies are being found once again in Burundi where politically-motivated violence will soon enter its third year, according to a U.N. human rights inquiry.

The central African nation has been in chaos since April 2015, when President Pierre Nkurunziza sparked widespread protests and an attempt to overthrow him by saying he would seek a third term.

The U.N. Human Rights Council set up a three-person commission of inquiry in September last year to identify perpetrators of killings and torture and ensure they were brought to justice.

“On the basis of a first set of interviews that we have conducted with various sources, it’s clear that the trends that were observed in 2015 and 2016 still exist,” the commission’s chairman Fatsah Ouguergouz told the Council.

“We have received testimonies saying that the phenomenon of the discovery of corpses, often mutilated, hung or with the arms bound, which was observed in 2015 and 2016, has resumed in the last few months. In many cases, it was not possible to identify the victims or suspects.”

Burundi has refused to cooperate with the inquiry.

Its ambassador, Rénovat Tabu, said it was a great shame that the investigators had swallowed allegations fabricated by the political opposition, which he said was hiding behind civil society, and manipulated information from minority political parties supported by foreign powers.

“My delegation is staggered at the content of this report that we have just heard,” Tabu told the Council.

Ouguergouz said that a release of political prisoners after a presidential decree on Jan. 3, 2017, had been a positive step, though limited in light of continuing arrests.

He said the decline in the rule of law had given rise to extortion and ransoming, and several sources suggested law and order was being privatized in the hands of the Imbonerakure, the youth wing of the ruling party.

“We are particularly concerned by the near-complete impunity enjoyed by those responsible for these violations. Even when victims or witnesses are able to identify suspected perpetrators, cases of prosecution of state officials, or those who appear to have their support, are rare,” Ouguergouz said.

Opposition supporters were being arrested arbitrarily and judged harshly or imprisoned without due process, he said.

The political crisis has driven 391,700 Burundians into exile since April 2015, and at least 27,000 have left so far this year, he said.